I have a very close friend who is like this. She's currently having a few health issues and her reliance on her Naturopath instead of a doctor really makes me afraid for her.
I think that a lot of people have a single negative experience with a doctor, and decide to go to some sort of alt-medicine route and they are greeted by someone with a smiling face and made welcome - it hooks them, even if it may not be good for them.
Not that all alt-medicine folks are bad news. I knew a guy who was a "chiropractor", but really was functionally a physiotherapist who also did low level chiropractic stuff. As opposed to a lot of Chiros who adjust you then let you go (knowing you'll come back because he just fixed the symptom not the issue), He'd give someone an adjustment and say "OK now, let's talk about what you can do in your daily life so that you don't look like a paper clip anymore, and here are some physio exercises to do to help keep you on track."
alt-medicine stuff has its place, but it is not a replacement for a doctor.